SD cards equipped with a wireless communication function or a wireless LAN function have been developed. In an SD card equipped with a wireless LAN function, the host cannot communicate with networks freely, and communications are performed independently using the wireless communication function of the SD card. Further, an SDIO card equipped only with a wireless communication function is not provided with a TCP stack, a group of programs compiled from a plurality of programs relating to the TCO/IP communications protocols, which are necessary for generating an application that performs communications via a wireless LAN. This demands the host to follow a complex procedure.